[TYPO3] Making querystrings SQL safe?

[Bob]

OK, after a bit more research I feel the the solution is probably to use 
USER_INT to call PHP's str_replace. But all the userFunc examples I can 
find use custom PHP functions, not standard ones. And my attempts to use 
a standard one haven't worked.

Could anyone point me toward an example that uses a standard PHP 
function? Or isn't this possible? Or is there a better way anyway?

I'd really appreciate any pointers...

Thanks,

Bob